1. Field of the Invention
The present invention relates in general to mirror devices of a type which is remotely controlled through wires, and more particularly to a mirror device which is equipped with a wire tensioning device for tensioning the wires to achieve assured remote control.
2. Description of the Prior Art
In order to clarify the task of the present invention, one conventional remotely controlled mirror device of wire type will be described with reference to FIG. 3 of the accompanying drawings.
Referring to the drawing, there is shown the conventional device 100, which is disclosed in Japanese Patent Second Provisional Publication No. 48-9897.
The conventional device 100 comprises a stay 11 fixed to, for example, a front side panel of a vehicle body (not shown), to which a mirror housing 12 is secured through bolts 14. Stationarily disposed within the mirror housing 12 is a mirror holder 16 which is connected to the stay 11 through a bracket 18. The mirror holder 16 is formed with a spherical projection 16a. Pivotally disposed in the mirror housing 12 is a mirror unit which comprises a mirror plate 20 and a back plate 22. As shown, the back plate 22 is formed at its thicker central portion with a spherical recess 22a into which the spherical projection 16a of the mirror holder 16 is slidably received in a manner to provide therebetween an articulated connection. The mirror unit is thus pivotal about the spherical projection 16a in universal directions.
Three flexible wires 24, 26 and 28 extend between the mirror unit and a control device 30 which is positioned at a distance from the mirror housing 12. The control device 30 has a control knob 32 projecting into a driver's cabin of the vehicle. Each wire 24, 26 or 28 is connected at one end to the mirror unit and passes through an opening 16b formed in the mirror holder 16 and through a tension adjuster 38, 40 or 42 and through an opening 36a formed in a body 36 of the control device 30 and is finally connected to a universally pivoting member 34 of the control device 30. In the disclosed example, the wires 24 and 26 pass through a common opening 36a of the control device 30.
Each wire 24, 26 or 28 is slidably received in a shield tube 44, 46 or 48 constructed of a closely spiralled wire. Thus, the wire and the shield tube constitute a bowden cable. The shield tube 44, 46 or 48 is divided into two parts, one extending between the mirror holder 16 and one end of the tension adjuster 38, 40 or 42, and the other extending between the other end of the tension adjuster 38, 40 or 42 and the body 36 of the control device 30.
Each tension adjuster 38, 40 or 42 has a longitudinally extending bore 38a, 40a or 42a the opposed end portions of which are threaded in mutually opposed directions. The inward ends of the two parts of each shield tube 44, 46 or 48 are screwed into the threaded bores of the tension adjuster 38, 40 or 42 from opposite directions.
Thus, it will be appreciated that when the control knob 32 of the control device 30 is manipulated, the three wires 24, 26 and 28 are moved longitudinally in the associated shield tubes 44, 46 and 48 forward or rearward thereby to pivotally move the mirror unit about the spherical projection 16a in the mirror housing 12. It will be further appreciated that by turning the tension adjuster 38, 40 or 42 about the axis thereof in a given direction, the entire length of the shield tube 44, 46 or 48 including the length of the adjuster is increased or decreased with respect to the associated wire 24, 26 or 28, thereby adjusting a tension applied to the wire.
However, due to its inherent construction, the conventional device 100 is subjected to the following drawbacks.
That is, as is described hereinabove, the tension adjustment of each wire must be carried out by awkwardly turning the tension adjuster by a certain degree, depending upon the technical experience possessed by an operator. This adjusting method, however, tends to produce a considerable difference in turning angle of each tension adjuster among the persons who manipulate the adjusters 38, 40 and 42. Furthermore, the setting of the mirror unit to its neutral position must be carried out by manipulating the three tension adjusters individually. This is troublesome and time-consuming work.